PR c++/92106 - ICE with structured bindings and -Wreturn-local-addr.

	* typeck.c (maybe_warn_about_returning_address_of_local): Avoid
	recursing on null initializer and return false instead.

	* g++.dg/cpp1z/decomp50.C: New test.

From-SVN: r277264

gcc/cp/ChangeLog

+2019-10-21  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/92106 - ICE with structured bindings and -Wreturn-local-addr.
+	* typeck.c (maybe_warn_about_returning_address_of_local): Avoid
+	recursing on null initializer and return false instead.
+
 2019-10-17  JeanHeyd Meneide  <phdofthehouse@gmail.com>
 
 	Implement p1301 [[nodiscard("should have a reason")]] + p1771 DR

gcc/cp/typeck.c

@@ -9355,8 +9355,10 @@ maybe_warn_about_returning_address_of_local (tree retval)
 	  tree base = DECL_DECOMP_BASE (whats_returned);
 	  if (TYPE_REF_P (TREE_TYPE (base)))
 	    {
-	      tree init = DECL_INITIAL (base);
+	      if (tree init = DECL_INITIAL (base))
 		return maybe_warn_about_returning_address_of_local (init);
+	      else
+		return false;
 	    }
 	}
       bool w = false;

gcc/testsuite/ChangeLog

+2019-10-21  Marek Polacek  <polacek@redhat.com>
+
+	PR c++/92106 - ICE with structured bindings and -Wreturn-local-addr.
+	* g++.dg/cpp1z/decomp50.C: New test.
+
 2019-10-21  Richard Biener  <rguenther@suse.de>
 
 	PR tree-optimization/92162

gcc/testsuite/g++.dg/cpp1z/decomp50.C

+// PR c++/92106 - ICE with structured bindings and -Wreturn-local-addr. 
+// { dg-do compile { target c++17 } }
+
+template <typename> struct B;
+template <typename _Tp> struct B<_Tp *> { typedef _Tp& reference; };
+struct C {
+  template <typename _Up> using rebind = _Up *;
+};
+template <typename _Iterator, typename> class D {
+public:
+  typename B<_Iterator>::reference operator*();
+  void operator++();
+};
+
+template <typename _Iterator, typename _Container>
+bool operator!=(D<_Iterator, _Container>, D<_Iterator, _Container>);
+template <typename _Tp> class F {
+public:
+  typedef _Tp value_type;
+};
+
+template <typename _Alloc> struct G {
+  template <typename _Tp> struct H { using type = C::rebind<_Tp>; };
+  using const_pointer = typename H<typename _Alloc::value_type>::type;
+};
+template <typename _Tp, typename _Alloc = F<_Tp>> class I {
+  typedef D<typename G<_Alloc>::const_pointer, int> const_iterator;
+
+public:
+  const_iterator begin();
+  const_iterator end();
+};
+
+struct A {
+  struct J {
+    int name;
+    int value;
+  };
+  I<J> members;
+  template <typename Key> const int *find(Key) {
+    for (const auto &[name, value] : members)
+      // See <https://gcc.gnu.org/ml/gcc-patches/2019-10/msg01107.html>
+      // for why we don't warn here.
+      return &value; // { dg-bogus "address of local variable" }
+    return nullptr;
+  }
+};
+int main() {
+  A a;
+  a.find("");
+}